Le 07/09/2023 à 11:23, Maxime Chevallier a écrit :

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Hello everyone,

This is the first RFC series introducing ethernet PHY numbering, in an
effort to better represent the link components and allow userspace to
configure these.

As of today, PHY devices are hidden behind the struct net_device from
userspace, but there exists commands such as PLCA configuration,
cable-testing, soon timestamping, that actually target the phy_device.

These commands rely on the ndev->phydev pointer to find the phy_device.

However, there exists use-cases where we have multiple PHY devices
between the MAC and the front-facing port. The most common case right
now is when a PHY acts as a media-converter, and is wired to an SFP
port :

[MAC] - [PHY] - [SFP][PHY]

FWIW when thinking about multiple PHY to a single MAC, what comes to my 
mind is the SIS 900 board, and its driver net/ethernet/sis/sis900.c

It has a function sis900_default_phy() that loops over all phys to find 
one with up-link then to put all but that one in ISOLATE mode. Then when 
the link goes down it loops again to find another up-link.

I guess your series would also help in that case, wouldn't it ?

Christophe